Force-responsive actuator



March 1968 c. E. CAMPBELL ET 3,374,709

FORCE"RESPONSIVE ACTUATOR Filed March 23, 1967 2 Sheets-Sheet l INVENTORS CLAUDE E. CAMPBELL ROBERT B. ABRAMS ATTORNEY March 26,1968 c.E. CAMPBELL ET AL 3,374,709

FQRCE-RESPONSIVE ACTUATOR Filed March 25, 1967 2 Sheets-Sneet 2 FIG. 2

I NVEN TORS CLAUDE E. CAMPBELL ROBERT B. ABRAMS EM 0. 3AM

ATTORNEY United States Patent 3,374,709 FORCE-RESPONSIVE ACTUATOR Claude E. Campbell, Levittown, Pa., and Robert B.

Abrams, Hamilton Square, N.J., assignors to Throkol Chemical Corporation, Bristol, Pa., :1 corporation of Delaware Filed Mar. 23, 1967, Ser. No. 625,432

Claims. (Cl. 89-1) ABSTRACT OF THE DISCLOSURE Actuator comprising a toggle joint one link of which is resiliently biased toward the pivotal axis of the other link thereof, and a plunger arranged to move the oined ends of said links toward an operating contact.

This invention relates to a force-responsive actuator and more particularly to a device that can advantageously be employed to detonate an explosive at a preselected depth in water or at any chosen altitude in the atmos phere.

Many of the devices heretofore available for detonating depth charges, air-burst bombs and the like are excess1ve ly complex and consequently expensive to manufacture. Furthermore, pressure-responsive detonating mechanisms of the prior art are difficult to calibrate so that they will operate at a definite pressure, and generally cannot be tested without being destroyed. In contrast with known devices, actuators in accordance with the present invention can readily be manufactured at low cost, can be tested without being destroyed, and can conveniently he cal;- brated so that they will operate at different environmental pressures within exact limits.

It is accordingly an object of this invention to provide an improved force-responsive actuator.

Another object of the invention is to provide a pressureresponsive actuating device the components of which can be manufactured and assembled at low cost.

An additional object of the invention is to provide a mechanism that can conveniently be adjusted to detonate depth charges at different depths or air-burst bombs at different altitudes.

The aforesaid and other objects of the invention are achieved by an actuator comprising two links which form a toggle joint, means for resiliently biasing said links into a first cocked position, means for varying the angle between said links when they are in said first cocked position, and means for moving said links from said first cocked position to a second operating position. A complete understanding of the principles of the invention will be obtained by consideration of the following specification, in which reference is made to the accompanying drawings wherein:

FIGURE 1 is a fragmentary, sectional view of a preferred embodiment of the invention, taken along a plane that includes the common longitudinal axis of certain components thereof;

FIGURE 2 is a fragmentary, sectional view of the same embodiment, taken along the aforesaid plane and illustrating certain components thereof in a position different from that illustrated in FIGURE 1;

FIGURE 3 is a sectional view of the same embodiment, taken along the aforesaid plane and illustrating components thereof as they appear in an actuating configuration; and

FIGURE 4 is a detail view of a component of the same embodiment.

Throughout the specification and the drawings, like reference numbers refer to like parts.

In FIGURE 1 the number generally designates a housing employed as support means for other components of an actuator in accordance with the invention, said housing having formed therein first and second cylindrical bores 12, 14 which extend inwardly from outer surfaces 16, 18 thereof, respectively. More particularly, second bore 14 communicates with first bore 12 at a point intermediate the ends thereof, and the longitudinal axes of said bores intersect and are disposed perpendicular to each other. A first hollow cylinder 20, provided at one end with an end closure 22, conformably fits within first bore 12 and is fixedly held therein by a retaining pin 24 retractably mounted in housing 10. The wall of first cylinder 20 includes a first aperture 26 which is aligned with second bore 14 and a second aperture 28 which is diametrically opposed to said first aperture on said first cylinder and aligned with a third bore 30 extending from first bore 12 to the outer surface of housing 10. The inner surface of first cylinder 20 is formed with right-hand threads 32 which extend from the open end of said first cylinder to a point adjacent first and second apertures 26, 28. A second hollow cylinder, generally designated by the number 34, comprises a first portion 36 the periphery of which engages threads 32, and a second portion 38 the periphery of which abuts the inner surface of first bore 12. Second portion 38 of second cylinder 34 is provided with an aperture 40 having a smaller diameter than bore 42 in first portion 36 of said second cylinder, thus forming a shoulder 44 in the orifice of the latter. As illustrated in FIGURE 4, an index mark 46 is inscribed on the surface of housing 10 adjacent the outer edge of first bore 12, and for a reason that will appear hereinafter calibration numbers 48 are spaced circumferentially about the outer surface of second cylinder 34 adjacent the edge thereof. To permit second cylinder 34 to be turned with a spanner wrench, two holes 50, 50' extend inwardly from the outer surface of the cylinder at diametrically opposed points thereon.

Slidably disposed within second cylinder 34 is a first cup-shaped piston 52 the open end of which faces the longitudinal axis 54 of second bore 14. The head of first piston 52 is formed with a cylindrical boss 56 the periphery of which slidably engages the wall of aperture 40 in second cylinder 34 and the outer end surface 58 of which is exposed to the environment outside housing 10. It will be apparent that the shoulder 44 on second cylinder 34 serves as a stop means for limiting the distance that first piston 52 can move from the longitudinal axis 54 of second bore 14. First cylinder 20 and piston 52 are provided with O-rings 60, 62, 64, respectively, to seal the interior -66 of said first cylinder from the environment outside housing 10.

Slidably disposed within first piston 52 is a second cupshaped piston 68 the open end of which faces away from the longitudinal axis 54 of second bore 14. One end of a spring 70 conformably fits within the cavity in second piston 68 and the other end of said spring extends from the open end of said piston and contacts the bottom surface of the cavity in first piston 52. As will be explained hereinafter, the described actuator is armed by movement of first piston 52 toward the longitudinal axis 54 of second bore 14, at which time second piston 68 is biased in the same direction by spring 70. Movement of both of the pistons in the direction of said axis 54 is limited, however, by second stop means in the form of a retaining ring 72 the periphery of which is engaged within a circumferentially extending groove formed on the inner surface of second cylinder 34.

A first link 74 is disposed within first cylinder 20 and has one end pivotally mounted thereto by means of a pin 76 the ends of which are fixedly positioned within two holes (not shown) formed in the wall of said first cylinder and located at diametrically opposed points thereon, said pin passing through a clearance hole 78 in first link 74 and its longitudinal axis intersecting the longitudinal axis of said first cylinder and being disposed perpendic- -ular thereto. The free end of first link 74 is disposed adjacent the longitudinal axis 54 of second bore 14 and is provided with a pivot pin 80 that extends through a hole in one end of a second link 82, the other end of said second link being connected by a pivot pin 84 to a boss 86 on the head of second piston 68. Thus first and sec* ond links 74, 82 form a toggle joint movement of which varies the longitudinal position of second piston 68 relative to second cylinder 34. As will be seen in the following discussion of the operation of the described actuator, this movement of the toggle joint formed by first and .second links 74, 82 is effected by a plunger 88 slidably disposed within second bore 14. One end of a cylindrical member 90 is positioned within second aperture 28 of first cylinder 20, with a shear pin 92 extending into a hole in said member and into a hole (not shown) in said housing and thereby maintaining said member in the position thereof illustrated in FIGURE 1 prior to actuation of the mechanism. Also, before the device is actuated a firing pin 94 which projects from member 91) is spaced from an end surface of a stab primer 96 connected to an explosive transfer lead 98.

FIGURE 1 illustrfiles the components of the preferred embodiment of the vention as they appear in an unarmed configuration, i.e., a configuration wherein the end surface of the head of first piston 52 abuts shoulder 44 on second cylinder 34 and the inner end of said piston is spaced from retaining ring 72. Preferably the lengths of first and second pistons 52, 68 and spring 70 are such that said spring is subjected to little or no compressive stress when said first and second pistons are positioned as illustrated in FIGURE 1, thus eliminating any possibility of a change in the resilience of the spring such as could occur if it were stored for a long period under compression. FIGURE 2 illustrates the components as they appear in an armed configuration, i.e., a configuration wherein first piston 52 has been displaced toward the longitudinal axis '54 of second bore 14 to bring its inner end into contact with retaining ring 72, and wherein the head of second piston 68 also abuts said retaining ring. This displacement of first piston 52 inwardly from the position thereof illustrated in FIGURE 1 is effected by an increase in pressure against the outer end surface 58 of the boss 56 on said first piston, such as can occur when housing is associated with a depth charge dropped into the sea or with a bomb falling through the atmosphere. It will be obvious that first piston 52 will not move toward the longitudinal axis of second bore 14 until environmental pressure is of such magnitude that it will compress spring 70, and that after said first piston contacts retaining ring 72 first and second links 74, 82 are resiliently biased by said spring into the position thereof illustrated in FIGURES l and 2'. Thereafter plunger 88 4 ward member 90, second piston 68 is moved away from retaining ring 72, (spring 70 being further compressed by this movement of second piston '68), but first piston 52 is held against the retaining ring by the environmental pressure acting against end surface 58. It will be evident that the force exerted axially against second piston 68 by the end of second link 82 connected thereto is a vector of the force exerted against the joined ends of first and second links 74, 82 by plunger 88, and that this force against said second piston will vary inversely to the angle a between the longitudinal axis of said second link and the longitudinal axis of first bore 12 (more specifically, as a cotangent function of the angle 0a).,Thl1S as plunger 88 moves the jointed ends of first and second links 74, 82 toward member 90, the force thereby exerted against second piston 68 tending to move it away from the longitudinal axis 54 of second bore 14 continues to increase. More specifically, the instantaneous rate of change of the force exerted against second piston 68 by the movement of the plunger 88 is a cosecant squared function of the angle a, thereby producing a snap action in the movement of first and second links 74, 82 after they have just begun to move. Hence when the environmental pressure outside housing 10 reaches a certain level, the joined ends of the links rapidly move into contact with member 90, which in turn is driven downwardly into tde aperture 28 in first cylinder 20 so that firing pin 94 pierces stab primer 96, and the explosive in transfer lead 98 is thereby detonated. The diameter and material of shear pin 92 are selected, of course, so that the pin will be sheared when the joined ends of first and second links 74, 82 strike member 90. V

The environmental pressure at which the described actuator will operate may be quickly and conveniently selected merely by turning second cylinder 34 to change its longitudinal position within first cylinder 20. Thus, for

cannot move the joined ends of first and second links 74, v

82 toward member 90 until the force resulting from the environmental pressure against the outer end surfaces of said plunger is suflicient to overcome the force exerted against second piston 68 by spring 70. Since the area of end surface 58 of first piston 52 is larger than that of the total area of the end surfaces of plunger 88, the force resulting from environmental pressure against said end surface 58 is greater, at any time, than the force exerted against the end surfaces of said plunger by the environmental pressure. Thus first piston 52 is moved into its armed position against retaining ring 72, as described 'hereinbefore, when the environmental pressure outside housing 10 reaches a certain level, and subsequently at a greater environmental pressure plunger 88 is moved toward first bore 12 and the joined ends of first and second links 74, 82 are thereby moved toward member 90. As the joined ends of first and second links 74, 82 move toexample, second cylinder 34 can be turned clockwise to move it closer to the longitudinal axis 54 of second bore 14 than it is in FIGURES 1, 2 and 3. Second piston 68 will then be closer to said axis 54, when the components of the actuator are in the armed configuration thereof illustrated in FIGURE 1, than it is in that drawing, Consequently, the angle or. between the longitudinal axis of second link 82 and the longitudinal axis of first bore 12 is increased, and a greater force must be applied against plunger 88 to move it, and the joined ends of said links, toward member 90. Thus the actuator will not operate until the environmental pressure outside housing 10 is higher than the pressure that would have caused operation at the previous setting of second cylinder 34. Obviously, counterclockwise rotation of second cylinder 34 to move it a greater distance from the longitudinal axis 54 of second bore 14 than is illustrated in FIGURES 1, 2' and 3 will result in the actuator being adjusted for operation at lower environmental pressure. The calibration numbers 48 (see FIGURE 4) on the outer surface of second cylinder 34 can quickly be aligned with index mark 46 on housing 10 to thereby select the pressure at which an explosive device associated with the described actuator will be detonated.

It will be recognized that various modifications can be made in the construction and arrangement of the components of the preferred embodiment of the invention without departing from the principles on which its operation is based. For example, means other than threads 32 may be employed to enable the longitudinal position of second cylinder 34 within first bore 12 to be varied. In some embodiments of the invention, second cylinder 34 may itself beeliminated and first piston 52 can be slidably engaged within first bore 12. Furthermore, actuators in accordance with the invention can be constructed with different means, such as guide rails, which will allow components to move along a single axis only. Although the described preferred embodiment of the invention is designed for operation at a selected environmental pressure, other embodiments can readily be designed to operate after a predetermined force of any kind acts upon an arming member (Le, a member that performs the function of first piston 52) and thereafter a second predetermined force acts on the operating member (Le, a member thatperforms the function of plunger 88). Accordingly, it is to be understood that the scope of the invention is limited only by the terms of the appended claims.

What is claimed is: 1. A force-responsive actuator comprising: support means; a first member mounted to said support means for movement along a first axis; a second member mounted to 'said support means for movement along a second axis disposed substantially perpendicular to said first axis;

a first link one end of which'is pivotally mounted to said support means, the pivotal axis of the connection between said first link and said support means being substantially perpendicular to said second axis;

a second link one end of which is pivotally connected to the free end of said first link, whereby said first and second links form a toggle joint, said links and said second member being arranged so that movement of the latter along said second axis in the direction of said first axis moves the joined ends of said links in the same direction, said links being inclined in the direction of said second member when in a first cocked position;

resilient means disposed between said first member and the other end of said second link, whereby said first and second links are urged into said first cocked position thereof when said first member is moved to a point on said first axis located a predetermined distance from said second axis;

guide means carried by said support means for maintaining the end of said second link not joined to said first link on a line substantially perpendicular to said second axis as the angular position of said second link is changed relative to said first axis;

stop means mounted to said support means for limiting the motion of said first member, and the motion of the end of said second link not joined to said first link, toward said second axis;

actuation means mounted to said support means and disposed on the side of said first and second links remote from said second member, said actuation means and said links being arranged so that when said second member is moved toward said first axis, and the joined ends of said links are thereby moved toward said actuation means, the latter is actuated after said second member has moved a predetermined distance.

2. An actuator as defined in claim 1 including adjustment means mounted to said support means for varying the angle between said first axis and the longitudinal axis of said second link when .said first and second links are in said first cocked position thereof.

3. A force-responsive actuator comprising:

a housing having therein first and second bores which extend inwardly from outer surfaces thereof, said second bore communicating with said first bore and extending laterally therefrom at a point intermediate the ends thereof;

a piston slidably disposed within said first bore between the longitudinal axis of said second bore and the surface of said housing;

first stop means on said housing for limiting the motion of said piston away from the longitudinal axis of said second bore;

a plunger slidably disposed within said second bore;

a first link disposed within said first bore and having one end thereof pivotally mounted to said housing, the pivotal axis of the connection between first link 6 and said housing being substantially perpendicular to the longitudinal axis of said second bore and spaced U l therefrom on the side thereof remote from said pis- & 1 ton, said first link extending toward said piston;

a second link one end of which is pivotally connected to the free end of said first link, whereby said first and second links form a toggle joint, said links and said plunger being arranged so that movement of the latter toward said first bore moves the joined ends of said links away from the inner end of said second bore, said links being inclined in the direction of said second bore when in a first cocked position;

resilient means disposed between said piston and the other end of said second link, whereby said first and 'second links are urged into said first cocked position thereof when said piston is moved to a point in said first bore located a predetermined distance from the longitudinal axis of said second bore;

guide means disposed Within said first bore for maintaining the end of said second link not joined to said first link the same distance from the wall of said first bore as the angular position of said second link is changed relative to the longitudinal axis of said first bore;

second stop means on said housing for limiting the motion of said piston, and the motion of the end of said second link not joined to said first link, toward the longitudinal axis of said second bore;

actuation means mounted to said housing and disposed on the side of said first and second links remote from said second bore and said plunger therein, said actuation means and said links being arranged so that when said plunger is moved toward said first bore, and the joined ends of said links are thereby moved toward said actuation means, the latter is actuated after said plunger has moved a predetermined distance.

4. An actuator as defined in claim 3 including adjustment means mounted to said housing for varying the angle between the longitudinal axes of said first bore and said second link when said first and second links are in said first cocked position thereof.

5. A force-responsive actuator comprising:

a housing having therein first and second bores which extend inwardly from outer surfaces thereof, said second bore communicating with said first bore and extending laterally therefrom at a point intermediate the ends thereof;

a first hollow cylinder fixedly disposed within said first bore and having formed in the wall thereof a first aperture communicating with said second bore and a second aperture diametrically opposed to said first aperture, at least a portion of the inner surface of said first cylinder between saidapertures and the outer end of said first cylinder having threads formed thereon;

a second hollow cylinder at least a portion of the periphery of which engages said threads on the inner surface of said first cylinder;

a first cup-shaped piston slidably disposed within said second cylinder, the open end of said first piston facing the longitudinal axis of said second bore and at least a portion of the outer surface of the closed end of said first piston being exposed to the environment outside said housing;

first stop carried by said housing for limiting the motion of said first piston away from the longitudinal axis of said second bore;

a second cup-shaped piston slidably disposed within said first piston, the open end of said second piston facing away from the longitudinal axis of said second bore;

a spring a portion of which is disposed within said second piston and a portion of which extends from the open end thereof;

second stop carried by said housing for limiting the a first link disposed within said first cylinder and having one end pivotally mounted thereto, the pivotal ton, whereby said first and second links form a toggle joint movement of which varies the longithe outer end surface of said plunger being exposed to the environment outside said housing, movement of said plunger inwardly from the outer surface of said housing bringing its inner end into contact with at least one of said first and second links axis of the connection between said first link and 5 and moving the joined ends of the latter away from said first cylinder being substantially perpensaid first aperture in said first cylinder;

dicular to the longitudinal axis of said second bore actuation means disposed within said second aperture and spaced therefrom on the side thereof remote in said first cylinder, said actuation means being from said second cylinder, the free end of said first l0 actuated when said plunger moves the joined ends of link being disposed adjacent the longitudinal axis said first and second links a predetermined distance of said second bore; from said first aperture in said first cylinder and into a second link one end of which is pivotally connected contact with said actuation means.

to the free end of said first link and the other end of which is pivotally connected to said second pis- 15 References Cltgd UNITED STATES PATENTS 2,014,393 9/1935 Mathsen 102-79 tudinal position of said second piston relative to said 9 955 11/1960 MacDonald second cylinder; a plunger slidably disposed within said second bore, SAMUEL W. ENGLE, Primary Examiner. 

